Molecular flux distribution from the thermal evaporation source using Monte Carlo method: The importance of interparticle collision

Gyeongho Hyun, Sungmoon Kim, Jonginn Im, Younghyuck Na, Kwangho Jeong, Hyunbok Lee, Yeonjin Yi

Research output: Contribution to journalArticle

Abstract

Molecular flux distribution is critical information to obtain uniform thin films using the thermal evaporation technique in vacuum. However, the flux distribution is a quite complex function depending on the geometry of evaporation sources and the individual motion of evaporated molecules. This makes it difficult to establish a model describing the flux distribution that is directly associated with the distribution of film thickness on the substrate. In this study, we found that the conventional analytic model severely deviates from the experimental flux distribution except in the simple case. Thus, we developed a numerical model based on the Monte Carlo method to simulate the angular flux distribution from a thermal evaporation source. In particular, interparticle collisions have been handled rigorously. Evaporated molecules were assumed to be point particles that collide with each other and adsorbed (emitted) on (from) the nozzle wall of the source. The interparticle collision probability was addressed with the rarefied gas dynamics and the cosine law of emission was adopted to simulate the adsorption/emission process at the nozzle wall. Finally, we compared the simulated flux distribution with experiments on the cylindrical nozzle with various aspect ratios and deposition rates. The simulation results show excellent agreement with experimental data, indicating that interparticle collision is a key parameter for accurate simulation.

Original languageEnglish
Pages (from-to)1233-1237
Number of pages5
JournalCurrent Applied Physics
Volume19
Issue number11
DOIs
Publication statusPublished - 2019 Nov

Fingerprint

Thermal evaporation
Monte Carlo method
Monte Carlo methods
evaporation
Fluxes
collisions
nozzle walls
Nozzles
rarefied gas dynamics
Molecules
Gas dynamics
Deposition rates
Film thickness
Aspect ratio
Numerical models
Evaporation
nozzles
aspect ratio
molecules
Vacuum

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physics and Astronomy(all)

Cite this

Hyun, Gyeongho ; Kim, Sungmoon ; Im, Jonginn ; Na, Younghyuck ; Jeong, Kwangho ; Lee, Hyunbok ; Yi, Yeonjin. / Molecular flux distribution from the thermal evaporation source using Monte Carlo method : The importance of interparticle collision. In: Current Applied Physics. 2019 ; Vol. 19, No. 11. pp. 1233-1237.
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Molecular flux distribution from the thermal evaporation source using Monte Carlo method : The importance of interparticle collision. / Hyun, Gyeongho; Kim, Sungmoon; Im, Jonginn; Na, Younghyuck; Jeong, Kwangho; Lee, Hyunbok; Yi, Yeonjin.

In: Current Applied Physics, Vol. 19, No. 11, 11.2019, p. 1233-1237.

Research output: Contribution to journalArticle

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